### What problem does this PR solve?
This PR fixes incorrect naming for PostgreSQL usage by replacing all
instances of `postgresql` with the correct `postgres` in the `db_type`
field. This resolves potential configuration errors and ensures
consistency when specifying the database type.
Also fixed handling of None for `get_queue_length`
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
Co-authored-by: cucusenok <BP-116: updated readme.md>
### What problem does this PR solve?
Before executing the SQL, remove tags in the format [ID: number] to
avoid execution errors.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
Co-authored-by: wangyazhou <wangyazhou@sdibd.cn>
### What problem does this PR solve?
#9082#6365
<u> **WARNING: it's not compatible with the older version of `Agent`
module, which means that `Agent` from older versions can not work
anymore.**</u>
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
